The present invention relates generally to rotating electrical machines and in particular to a synchronous rotating machine having a permanent magnet rotor.
The document "Comparison of different synchronous motor drives for flux weakening applications", N. Bianchi et al., proceedings of the International Conference on Electrical Machines (ICEM), Istanbul, Turkey, September 1998, volume 2/3, pages 946 et seq, and in particular FIG. 5 of the document and the associated description, discloses a machine whose rotor is separated into two coaxial parts disposed end-to-end in the axial direction.
A first part of the rotor constitutes an excitation magnet rotor and the other part constitutes a variable reluctance rotor.
Although a machine of the above kind has beneficial properties, in particular in terms of flux weakening if the machine has to operate under reduced load conditions, a major drawback is that it is necessary to provide two types of yoke for rotor structure, i.e. a yoke for the permanent magnet part of the rotor and a yoke for the variable reluctance part of the rotor.
A first object of the present invention is to alleviate this drawback and to provide a rotor operating in accordance with the same principle using a single yoke.
To be more precise, the present invention proposes to combine the two rotor parts into a single rotor whose yoke can therefore be made with a single lamination shape.